It's 6MB because ASUS doesn't include the ME Region inside the SPI image. Also, ASUS always has an AMI Capsule header at their BIOS images. So, in order to flash it with a programmer, you need to a) remove the AMI Capsule Header and b) include the ME Region at the SPI image. First, dump the chip and attach the 8MB resulting image.

That's a problem, you need to find online someone else's dump of the exact same model first. We can take the ME Region from there in such case and clean it while retaining ASUS model settings before applying it to your system.

Well from a quick search I can see one 8MB dump HERE (search for S550CM) but you need to register or something, hopefully no VIP/money is asked after that. Give it a try. And since you have access to the chip and mobo, check if the model of the latter is indeed K56CM Rev 2.0 as that site seems to report the dump came from.

By searching for EFI_SUCCESS tag via a Hex Editor, you can see from what motherboard these were dumped from. I chose dump2.bin because it reported K56CM instead of K56CB that dump.bin did even though I noticed that dump.bin and the original ASUS bios are a lot more similar. Doesn't matter, since you don't have your own dump, I replaced the entire BIOS region with the one ASUS provides. What I did:

1) Used dump2.bin as the base for the rest of the regions (FD, GbE and ME).2)Cleaned the ME Region by removing any dumped DATA which can cause problems.3) Replaced the BIOS Region with the one from ASUS website for your model.

I could also have updated the ME to the latest but since you can do this yourself once the system is running, I left it to you. In the end, I have attached the final file for you. Flash it, perform a CMOS and let me know how it goes.

That's great. Since you had no personal older dump, you may have lost some ASUS Serial Numbers and such (in case they were displayed at the BIOS) but at least the system is operational now. To be 100% certain, use Flash Programming Tool with command fptw -greset once to reset the ME status. Afterwards, updating the ME is easy: visit the ME thread, download latest ME8 1.5MB, flash with FWUpdate and after a restart check if everything is ok with MEInfo and MEManuf. All links, instructions etc can be found at the ME thread. If you want to mod some aspects of the BIOS (for example microcode, lan) then you can use UEFI Bios Updater. Lastly, you can also use Flash Programming Tool to dump, mod and flash the BIOS quickly. The ASUS tool will probably require the AMI Capsule with integrity signature checking and so on. You don't have to worry about any such things with FPT but if you plan to use it, be careful with it and make sure you type each command correctly.

Obviously. That's completely wrong, I said to be careful with FPT. All you did is flash your entire 8MB SPI chip with the ME firmware.

At the ME thread, where you can find all the mentioned tools, firmware and instructions, it's clearly stated that the tool to update the ME firmware is FWUpdate and not FPT. So it's FWUpdLcl -f ME.bin.

If you were to flash the ME Region with FPT, which you don't need to do because a) you would have to move settings with Flash Image Tool and b) FWUpdate is all you need to update and not replace the region in case it's corrupted, the correct command would have been fpt -f me.bin -me. I'm fairly certain that FPT warned you that you were going to flash something of a smaller size too.

I mentioned FPT before in order to flash the BIOS, not any other region of the SPI image. BIOS does not mean SPI Image, it's a part of it.

So, you now need to reflash the SPI image I made earlier. Then there are two choices: either make sure the system is working and leave it as it is or read the guides/threads carefully and only then proceed with any kind of module updating. Not being careful and not reading instructions will only result in more bricks and hassle.

ASUS doesn't include the Nvidia VBIOS for some reason at that model's BIOS. Probably a mistake. Normally you should contact them and ask them to fix that mistake. Transferring the nvidia vbios of another model is risky as it may work but not behave properly under heavy load. I found another ASUS model which uses the same gpu with same amount of RAM of the same generation, ASUS N56VJ. I took it's nvidia vbios and placed it at the BIOS of your own model. That modded BIOS is attached. I do not guarantee that this will work, it may, it may not. Test the gpu under heavy load as well for stability if it gets detected first. Flash the attached BIOS region via Flash Programming Tool using command fptw -f S550CAAS_NV.bin -bios followed by a fptw -greset . Again, you should contact ASUS, this is just a test.